The present invention relates to an orthosis intended to be placed on the hand of a user, in particular to treat rhizarthrosis.
Rhizarthrosis—or arthrosis of the base of the thumb—is the wear of the cartilage of the joint at the base of the thumb, between the trapezius and the metacarpal bone. Aside from the pain it causes, this pathology can cause joint stiffness and deformation of the thumb, preventing the grasping of an object between the thumb and the index or other fingers. There is also a risk of luxation of the joint.
Orthopedic treatment of rhizarthrosis aims on the one hand to decrease pain, and on the other hand to prevent the loss of range of movement, i.e. the impossibility of moving the thumb away from the index finger.
Several types of orthoses of the hand used to treat rhizarthrosis are already known.
According to a first known embodiment, such an orthosis consists of a rigid piece made from a thermoformable material. The intervention of an orthotist is generally required to customize this piece. An orthosis of this type is therefore restrictive and expensive to produce. Furthermore, it cannot be easily adapted to wearing conditions, typically daytime wear and nighttime wear.
According to a second known embodiment, such an orthosis consists of a textile strap, possibly provided with stiffeners, that the user winds and fastens around his hand. This orthosis is generally difficult for the user to place alone. Furthermore, poor positioning can be detrimental to the orthopedic treatment.
Another hand orthosis to treat rhizarthrosis is proposed in document WO 2006/117808. The orthosis described in this document has a certain number of drawbacks.
First of all, it is fairly difficult to place, in particular when it involves positioning the additional band surrounding the finger, which is necessary to maintain the piece on which the thumb rests.
Furthermore, in order to obtain effective immobilization of the area of the lesion, this orthosis blocks other zones, whereas this is not directly necessary for the concerned pathology. This in particular involves the distal part of the thumb, the base of the long fingers, and an extended area around the joint of the wrist. This causes a significant limitation of the movements of the hand, which makes the orthosis fairly uncomfortable and impractical, and may dissuade some people from wearing it.